It must be borne in mind that there are two categories of inadmissible evidence. Evidence that is absolutely inadmissible in law which is not within the competence of the parties to admit by consent or otherwise. It is a document which is by law inadmissible, see for example James v Mid Motors (1978) 11-12 SC 31; Minister v Azikiwe (1969) 1 All NLR 49; Kale v Coker (1982) 12 SC 252. The second class of inadmissible evidence is, for example, a document which is admissible in law but upon fulfilling certain conditions, parties may by consent admit it notwithstanding the conditions not being fulfilled e.g. the admission of unstamped instrument required to be stamped, see Etim v Ekpe (1983) 1 SC NLR 120, (1983) NSCC 86; Igbodim v Obianke (1976) 9-10 SC 179.
— Musdapher, JSC. Shittu & Ors. v Fashawe [2005] – SC 21/2001